Unique Diaphragm Seal Solutions

At Bliss Anand America, we don’t like saying the word no. We know that we have experienced engineering and production teams, and armed with the right tools, we believe they can solve any problem.

So when BP came to us with a unique solution, we put our best people to the test. Working with our partners Badotherm, Bliss created a special solution to suit BP’s requirements.

The Application:

  • Very high process 
temperature – 760°F
  • Small process connection – 
no larger than 1”
  • Process fluid is a gas with high levels of hydrogen, and small amounts of H2S and NH3

The Concerns:

  • Are there any fill fluids that handle temperatures up to 760°F?
  • EJX430 (preferred Yokogawa gauge pressure transmitter) can only handle up to 248°F
  • Durability of gold coating – specifically regarding thermal shock at startup
  • Materials and NACE certification requirements

Bliss-Badotherm’s ApproachIMG_1625

  • Use BSO-48 as a fill fluid to handle temperatures ranging from -4 – 788°F
  • Use EJX530A transmitter rather than EJX430, as it contains fully welded construction (no gaskets or threads). It is highly recommended for high temperature/high pressure applications
  • Supply a 1 piece BF design with a thermal reducer
  • Supply gold-coated seal with 40μm on 316L diaphragm and other wetted parts. Alloy 400 specified by customer is only suitable for temperature below 392°F

Through perseverance, a lot of back and forth and discussion, and a creative mindset for solving problems, Bliss-Badotherm is now the only supplier (globally) for gold-coated seals with high temperature fill fluids.

IMG_1626

For more information about our Gold-Coating, download our brochure here: Badotherm Diaphragm Seal Solution Gold Coating

For more information about our High Temperature Diaphragm Seals, download our brochure here: htds-seal-solutions

PTH Diaphragm Seals

Screen Shot 2017-03-07 at 1.56.46 PMPTH Diaphragm Seals were designed as an alternative to the existing Rosemount High Process Temperature Transmitter. The seal, which can be directly mounted onto a transmitter without the use of remote seals or capillaries, can go up to temperatures as high as 392°F (200°C), though by using different fill fluids the temperature can go even higher, up to 788°F (420°C). This solution makes it possible to measure differential or gauge pressure at high process temperatures through a direct mounted seal.

The PTH Seal is designed and manufactured to meet the requirements of IEC 61518, with all the wetted parts constructed from AISI 316 (L).

 

Specifications

Maximum Temperature
Using BSO-22, the maximum process temperature it can withstand is 392°F (200°C). In combination with other filling fluids, the maximum process temperature can increase to 788°F (420°C).

Maximum Static Pressure

  • 200 bar / 392°F (200°C)
  • 250 bar / 68°F (20°C)
  • 350 bar / 68°F (20°C) (design)

Reference Accuracy
0,025% for the Diaphragm Seal + transmitter specifications

Mounting Position Effects
Zero shifts up to 15 mbar (at 180°C), which can be calibrated out. There is no span effect.

Mounting
The PTH dimensions are designed according to the IEC standard 61518 and the seal is suitable for mounting to the process connectors according the DIN19213 1982 part 2 for manifold mounts.

Special Materials and CoatingsScreen Shot 2017-03-07 at 1.58.26 PM
The PTH Seal can be supplied with various exotic
diaphragm materials, including Hastelloy C276, Monel or Tantalum. The process flanges can also be supplied with these exotic materials. Other materials are available on request.

For Hydrogen applications, the PTH Seal Diaphragm can be Gold Coated.

 

Temperature Effect

Options Temperature effect
Standard 0,24 mbar / Δ50°F
With temperature test 0,15 mbar / Δ50°F


Temperature Limits

Filling fluid Temperature specifications
BSO-22 (standard) -40°F to 392°F
BSO-40 (FDA approved)    5°F to 455°F
BSO-18 14°F to 599°F
BSO-42 14°F to 662°F
BSO-48 -4°F to 788°F

 

Gold Coated Diaphragm Seals

Hydrogen is not typically considered corrosive, but as a common element in diaphragm seal applications, there are certain circumstances where it may cause issues. For these times, Bliss Anand America and Badotherm Netherlands offer you a solution – Gold Coated Diaphragm Seals. The gold protects the fill fluid from becoming saturated with hydrogen, leading to more accurate measurement for your project.

So what is hydrogen permeation?

Hydrogen is usually found is a diatomic state, as two hydrogen atoms, or H2. These molecules do not permeate a regular sized diaphragm, at a standard thickness of 75 μm. However, under certain pressures and temperatures, the diatomic hydrogen splits into two H+ ions that are smaller than the space between the molecules of the material used to construct a regular diaphragm. This allows the H+ ions to slip between the cracks. Having permeated the diaphragm, the H+ icons join back into H2, dissolving into, and eventually saturating, the fill fluid. Over time, hydrogen gas bubbles form, altering the performance of the mounted transmitter.

regular

The Bliss Anand America – Badotherm Netherlands Solution

Gold is a noble metal, which means it is more resistant to corrosion than most other materials. Adding a layer of gold to a base metal provides an extra layer of protection to the seal. The H+ ions are not able to permeate the gold diaphragm foil, allowing your fill fluid to remain pure.

gold-coated

We take our seals the extra mile beyond our competition, and for increased security at extreme conditions, we offer 40µm thickness that can withstand temperatures up to 752 °F (400 °C). This design is approved by international end-users including Royal Dutch Shell.

Gold also increases the chemical resistance of the seals, and can therefore be used in multiple ways:screen-shot-2017-02-06-at-12-42-40-pm

  • To protect against hydrogen permeation, as described above, only the diaphragm is coated.
  • To increase chemical resistance, the coating can be extended to the outside diameter of the gasket surface.

 

Do your diaphragm seals need the gold standard of protection? Download a brochure here for more information or give us a call at 281.479.2547 to speak to our sales team.